1. Field of the Invention
This invention relates generally to motor load testing systems and apparatus used to measure torque and speed characteristics of motors.
2. Description of the Prior Art
Traditionally, torque and speed characteristics of motors have been measured with dynamometers. In absorption dynamometers, braking force is applied to the machine being tested and torque is determined from the amount of force required to reduce the motor speed to some full-load value. Dynamometers of this type absorb the total power delivered by the machine being tested. In addition to the energy dissipated in the brake, large machines may require cooling water systems for the heat generated that include additional cooling tower, pumps, and sewage costs. Comparatively, resistance type loading of a generator driven by a test motor has similar large costs where energy is wasted. In addition, whenever energy is wasted utilizing these methods, higher demand capabilities are required from the utilities at a cost above normal operating demand capacities. Other means such as direct current motor generator sets require more investment in capital equipment, more sophisticated control and considerably lower overall efficiency. Today's energy demands make efficient use of power a necessity. Consequently, conventional torque testing apparatus and systems can be extremely expensive.